Direactive mesogenic compounds and intermediates

ABSTRACT

The invention relates to direactive mesogenic compounds or mixtures thereof comprising mesogene-containing molecules, said mesogens having two side chains attached thereto which contain a terminal polymerizable functional group, said mesogens and said functional groups being separated by spacer groups having at least two to twenty spacer atoms, wherein both spacer groups have different chain length.

The invention relates to direactive mesogenic compounds or mixtures thereof obtainable by

a) treating a mesogenic diol of formula I,

    HO-MG-OH                                                   (I)

in which

MG is a mesogenic group,

with a mixture of the halides of formula II and III,

    X.sup.1 --(CH.sub.2).sub.m --R.sup.a                       (II)

    X.sup.2 --(CH.sub.2).sub.n --R.sup.b                       (III)

in which

X¹ and X² are each independently Cl, Br or I,

m and n are different integers between 1 and 20

R^(a) and R^(b) are each independently groups selected from

--CH₂ OH or --CH═CWH

wherein

W is H, CH₃ or Cl,

in the presence of a base, and

b) treating the resulting intermediate

in the case of R^(a) and R^(b) being --CH₂ OH, with a vinyl derivative of formula CH₂ ═CW--(CO)_(a) --O-- or a reactive derivative thereof, in which a is 0 or 1

in the case of R^(a) and R^(b) being CH═CWH with a perbenzoic acid.

The invention furthermore relates to the preparation of such compounds and to their use in electrooptical scattering systems and for the preparation of oriented liquid crystal polymers.

Reactive liquid crystal compounds can be polymerized in situ, whilst in their liquid crystal phase, to give highly crosslinked anisotropic films which can be used, for example, as polarizing beam splitters (see, for example, EP 0,428,213). Reactive liquid crystal compounds have furthermore been proposed for electrooptical scattering systems (see, for example, EP 0,451,905), cholesteric polarizers (e.g. EP 0,606,940) and compensation films for STN displays (e.g. EP 0,423,881).

Reactive liquid crystal diesters of formula ##STR1## are mentioned in EP 0,261,712 (n=o), EP 0,331,233 (n=1). Reactive liquid crystal biphenyls of formula ##STR2## are disclosed by EP 0,405,713.

The International Patent application WO 93/22397 discloses a compound of formula ##STR3##

These reactive liquid crystalline compounds often exhibit, however, rather high melting points disadvantageous values of the birefringence and comparable narrow mesophase ranges.

In view of the broad range of applications of reactive liquid crystal compounds it was desirable to have available further compounds of this type which fulfill the various requirements such as a reasonably low melting point, a high birefringence, a broad mesogenic range and preferably an enantiotropic nematic range to a high degree.

It was an object of the present invention to provide new reactive liquid crystalline compounds with advantageous properties thus extending the pool of reactive liquid crystal compounds available to the expert. Other objects of the present invention can be taken from the following detailed specification.

The present invention thus relates to reactive mesogenic compounds or mixtures thereof obtainable by treating mesogenic diols of formula I, in particular those having a symmetric structure unit with a mixture of halides of formula II and III and to their use in electrooptical systems of scattering type and for the preparation of oriented liquid crystal polymers. The invention furthermore relates to the preparation of compounds according to formula I.

Preferred embodiments of the present invention are:

a) Composition of direactive compounds comprising at least one compound of each formula IV, V and VI,

    R.sup.1 --(CH.sub.2).sub.m --O-MG-O--(CH.sub.2).sub.n --R.sup.2IV

    R.sup.1 --(CH.sub.2).sub.m --O-MG-O--(CH.sub.2).sub.m --R.sup.1V

    R.sup.2 --(CH.sub.2).sub.n --O-MG-O--(CH.sub.2).sub.n --R.sup.2VI

in which MG, m and n have the meaning given, and

R¹ and R² are each independently ##STR4## b) Direactive compound or mixture thereof in which

m-n≧1, in particular 2, 3 or 4.

c) Direactive compound or mixture thereof in which

MG is a mesogenic group of formula VIII,

    --(A.sup.1 --Z.sup.1).sub.o --A.sup.2 --                   VIII

in which

A¹ and A² are each independently

(a) 1,4-phenylene in which one or two CH groups may be replaced by N;

(b) 1,4-cyclohexylene in which one or two non-adjacent CH₂ groups may be replaced by --O-- or one --CH-- group may be replaced by --C(CN)--;

(c) naphthaline-2,6-diyl;

it being possible that group (a) is substituted by halogen cyano or alkyl, alkoxy or alkanoyl with 1 to 6 C atoms,

Z¹ is each independently --COO--, --O--CO--, --CH₂ --CH₂ --, --C.tbd.C--, --CH₂ O--, --OCH₂ -- or a single bond, and

o is 1, 2 or 3.

d) Direactive compound or mixture thereof in which MG is selected from the structure elements (1) to (6). ##STR5## in which L is CH₃, Cl, F, OCH₃ or --CO--CH₃, and

r is 0, 1, 2 or 4.

e) Direactive compound or mixture thereof in which

n and m are given by the following table:

    ______________________________________                                         m      5          5     5        4   4                                           n 2 3 4 2 3                                                                  ______________________________________                                    

A further aspect of the present invention is direactive compounds of formula IV A

    R.sup.1 --(CH.sub.2).sub.m O-MG-O--(CH.sub.2).sub.n --R.sup.2(IVA)

in which

R¹ and R² have the meaning given,

m and n are different integers between 2 and 10, and

MG is a mesogenic group, the core of which being symmetrical, preferably a structure element of formula (1), (5) or (6), in particular direactive compounds of the formula IVA1 ##STR6## in which R¹, R²,

L and r have the meaning given,

m and n are different integers between 2 and 10, and

t is 0 or 1.

Other aspects of the invention are the polymers prepared by polymerizing a monomer as described above and

chemical intermediate compounds or mixtures thereof useful in preparing direactive compounds or mixtures thereof as described above, comprising mesogene-containing molecules, said mesogenes having two side chains attached thereto that contain hydroxyl or vinyl group at the end thereof, said mesogenes and said functional groups being separated by at least two to twenty spacer atoms, wherein both spacer groups have different chain length.

Above and below, the term reactive mesogenic compounds refers to reactive rod-like molecules which may be enantiotropic, monotropic or isotropic, preferably, however, enantiotropic or monotropic.

In the inventive compounds in which MG is a mesogenic group of formula VIII, A¹ and A² can be independently from each other an unsubstituted or a substituted 1,4-phenylene group of formula ##STR7## X², X³, X⁵ and X⁶ can be independently from each other H, F, Cl, methyl or CN.

In the following, for the sake of simplicity, the following notation will be used:

Phe. 2 X² 3 X³ 5 X⁵ 6 X⁶ is a 1,4-phenylene group carrying in 2-position the group X², in 3-position the group X³ etc.; in case X², X³, X⁵ and/or X⁶, denote H, this will not be specified in above notation, i.e. only true substitutions will be listed. Thus Phe, for example, is an unsubstituted 1,4-phenylene group while Phe.2F 5 Cl is a 2-fluoro-5-chloro-1,4-phenylene group. Furthermore, Pyr is pyrimidine-2,5diyl, Pyd is pyridine-2,5-diyl and Nap is a naphthalene-2,6-diyl group. The notation Pyr and Pyd in each case include the 2 possible positional isomers.

The compounds according to formulae IV comprise 2- and 3-ring compounds (n=1 or 2) of formula IV2 and IV3:

    R.sup.1 --(CH.sub.2).sub.m --O--A.sup.1 --Z.sup.1 --A.sup.2 --O--(CH.sub.2).sub.n --R.sup.2                           IV 2

    R.sup.1 (CH.sub.2).sub.m --O--A.sup.1 --Z.sup.1 --A.sup.1 --Z.sup.1 --A.sup.2 --O--(CH.sub.2).sub.n --R.sup.2                 IV 3

In the 3-ring compounds of formula IV3, the ring groups A¹ can be chosen independently from each other.

Especially preferred is a smaller group of 2-ring compounds exhibiting the following structures for --A¹ --Z¹ --A² --:

    ______________________________________                                         Phe.2CH.sub.3 -Phe- IV2-1                                                       Phe.3CH.sub.3 -Phe- IV2-2                                                      Phe.2Cl-Phe- IV2-3                                                             Phe.3Cl-Phe- IV2-4                                                             Phe.2CN-Phe- IV2-5                                                             Phe.3CN-Phe- IV2-6                                                             Phe.2Cl3Cl-Phe- IV2-7                                                          Phe.2Cl3F-Phe- IV2-8                                                           Phe.2F-Phe- IV2-9                                                              Phe.3F-Phe- IV2-10                                                             Phe.-Phe- IV2-11                                                               Phe.F-Nap- IV2-12                                                              Phe.2Cl-Nap- IV2-13                                                            Phe.F-Nap- IV2-14                                                              Phe.3Cl-Nap- IV2-15                                                            Phe.2F-Pyr- IV2-16                                                             Phe.2F-Pyr- IV2-17                                                             Phe.2CH.sub.3 -Pyd- IV2-18                                                     Phe.2Cl-Pyd- IV2-19                                                            Phe.F--CH.sub.2 CH.sub.2 -Phe- IV2-20                                          Phe.3F--CH.sub.2 CH.sub.2 -Phe- IV2-21                                         Phe.2Cl--CH.sub.2 CH.sub.2 -Phe- IV2-22                                        Phe.3Cl--CH.sub.2 CH.sub.2 -Phe- IV2-23                                        Phe.2CN--CH.sub.2 CH.sub.2 -Phe- IV2-24                                        Phe.3CN--CH.sub.2 CH.sub.2 -Phe- IV2-25                                        Phe.2Cl3Cl--CH.sub.2 CH.sub.2 -Phe- IV2-26                                     Phe.2Cl3F--CH.sub.2 CH.sub.2 -Phe- IV2-27                                     ______________________________________                                    

The 3-ring compounds according to formula IV3 preferably exhibit the following structures for --A¹ --Z¹ --A¹ --Z¹ --A² : ##STR8##

In these structures, IV3-a to IV3-d, L¹ and L² denote independently from each other H, --Cl, --F, --CN and C_(r) H_(2r+1-s) and, in particular, --Cl, --F, --CN, --CH₃, and/or --C₂ H₅.

Especially preferred are the following patterns:

    ______________________________________                                         Phe-Phe.2CH.sub.3 -Phe-  IV3-a-1                                                Phe-Phe.2Cl-Phe- IV3-a-2                                                       Phe-Phe.2CN-Phe- IV3-a-3                                                       Phe-Phe.2F-Phe- IV3-a-4                                                        Phe-Phe-Phe- IV3-a-5                                                           Phe-Phe.2C.sub.2 H.sub.5 -Phe- IV3-a-6                                         Phe-Phe.3CH.sub.3 -Phe- IV3-b-1                                                Phe-Phe.3Cl-Phe- IV3-b-2                                                       Phe-Phe.3CN-Phe- IV3-b-3                                                       Phe-Phe.3F-Phe- IV3-b-4                                                        Phe-Phe.3C.sub.2 H.sub.5 -Phe- IV3-b-5                                         Phe.3F-Phe.3Cl-Phe- IV3-b-6                                                    Phe.3F-Phe.3CH.sub.3 -Phe- IV3-b-7                                             Phe.3Cl-Phe.3Cl-Phe- IV3-b-8                                                   Phe.3Cl-Phe.3CH.sub.3 -Phe- IV3-b-9                                            Phe-Phe.2Cl-Phe.3Cl-- IV3-b-10                                                 Phe-Phe.3Cl-Phe.3Cl-- IV3-b-11                                                 Phe-Phe.2Cl-Phe.2Cl-- IV3-b-12                                                 Phe-Phe.3Cl-Phe.2Cl-- IV3-b-13                                                 Phe-Phe.2CH.sub.3 -Phe.3Cl-- IV3-b-14                                          Phe-Phe.3CH.sub.3 -Phe.3Cl-- IV3-b-15                                          Phe-Phe.2CH.sub.3 -Phe.2Cl-- IV3-b-16                                          Phe-Phe.3CH.sub.3 -Phe.2Cl-- IV3-b-17                                          Phe-Phe.2F-Phe.3Cl-- IV3-b-18                                                  Phe-Phe.3F-Phe.3Cl-- IV3-b-19                                                  Phe-Phe.2F-Phe.2Cl-- IV3-b-20                                                  Phe-Phe.3F-Phe.2Cl-- IV3-b-21                                                  Phe-Phe.2Cl-Phe.3CN-- IV3-b-22                                                 Phe-Phe.3Cl-Phe.3CN-- IV3-b-23                                                 Phe-Phe.2Cl-Phe.2CN-- IV3-b-24                                                 Phe-Phe.3Cl-Phe.2CN-- IV3-b-25                                                 Phe-Phe.2CH.sub.3 -Phe.3CN-- IV3-b-26                                          Phe-Phe.3CH.sub.3 -Phe.3CN-- IV3-b-27                                          Phe-Phe.2CH.sub.3 -Phe.2CN-- IV3-b-28                                          Phe-Phe.3CH.sub.3 -Phe.2CN-- IV3-b-29                                          Phe-Phe.3F-Phe.3CN-- IV3-b-30                                                  Phe-Phe.2F-Phe.3CN-- IV3-b-31                                                  Phe-Phe.3F-Phe.2CN-- IV3-b-32                                                  Phe-Phe.2F-Phe.2CN-- IV3-b-33                                                  Phe-Phe.2F-Phe.2F-- IV3-b-34                                                   Phe-Phe.3F-Phe.3F-- IV3-b-35                                                   Phe-Phe.2CH.sub.3 --C.sub.2 H.sub.4 -Phe- IV3-c-1                              Phe-Phe.2Cl--C.sub.2 H.sub.4 -Phe- IV3-c-2                                     Phe-Phe.2CN--C.sub.2 H.sub.4 -Phe- IV3-c-3                                     Phe-Phe.2F--C.sub.2 H.sub.4 -Phe- IV3-c-4                                      Phe-Phe.2C.sub.2 H.sub.5 --C.sub.2 H.sub.4 -Phe- IV3-c-5                       Phe-Phe.2Cl3F--C.sub.2 H.sub.4 -Phe- IV3-c-6                                   Phe-Phe.2Cl3Cl--C.sub.2 H.sub.4 -Phe- IV3-c-7                                  Phe-C.sub.2 H.sub.4 -Phe.2CH.sub.3 --C.sub.2 H.sub.4 -Phe- IV3-c-8             Phe-C.sub.2 H.sub.4 -Phe.2Cl--C.sub.2 H.sub.4 -Phe- IV3-c-9                    Phe-C.sub.2 H.sub.4 -Phe.2CN--C.sub.2 H.sub.4 -Phe- IV3-c-10                   Phe-C.sub.2 H.sub.4 -Phe.F--C.sub.2 H.sub.4 -Phe- IV3-c-11                     Phe-C.sub.2 H.sub.4 -Phe.2OCF.sub.3 --C.sub.2 H.sub.4 -Phe- IV3-c-12           Phe-COO-Phe.OCO-Phe- IV3-d-1                                                   Phe-COO-Phe.2CH.sub.3 --OCO-Phe- IV3-d-2                                       Phe-COO-Phe.3CH.sub.3 --OCO-Phe- IV3-d-3                                       Phe-COO-Phe.2CH.sub.3 3CH.sub.3 --OCO-Phe- IV3-d-4                             Phe-COO-Phe.2OCH.sub.3 --OCO-Phe- IV3-d-5                                      Phe-COO-Phe.2Cl--OCO-Phe- IV3-d-6                                              Phe-COO-Phe.2F--OCO-Phe- IV3-d-7                                               Phe-COO-Phe.2F3F--OCO-Phe- IV3-d-8                                             Phe-COO-PhePhe- IV3-e-1                                                        Phe-COO-Phe.2FPhe- IV3-e-2                                                     Phe-COO-Phe.3FPhe- IV3-e-3                                                     Phe-COO-PhePhe.2F-- IV3-e-4                                                    Phe-COO-PhePhe.3F-- IV3-e-5                                                    Phe.2F--COO-PhePhe- IV3-e-6                                                    Phe.3F--COO-PhePhe- IV3-e-7                                                   ______________________________________                                    

It was observed that the stability of 3-ring compounds wherein one of the 2 groups Z¹ is --COO-- or --OCO-- while the other denotes a single bond, can be increased if the compound is laterally di- or higher substituted, particularly di-substituted by --Cl, --F, --CN and/or --CH₃. Compounds of this type are preferred.

Especially preferred are further 3-ring compounds where both groups Z¹ are either --COO--, or --OCO-- and at least one of the rings A¹, A¹ ' and A² are at least mono substituted.

In the compounds of formula IV R¹ is CH₂ =CW--COO--CH₂ --, CH₂ ═CH--O--CH₂ -- ##STR9## with W being H, Cl or alkyl with 1-5 C atoms and m being 1-7.

Preferably, R¹ and R² is a vinyl group, an acrylate group, an epoxy group and especially preferred are the following means of R¹ and R² : ##STR10## with alkyl denoting C₁ -C₃ -alkyl and m being 1-5.

The reaction methods mentioned are briefly summarized in the following synthetic tree: ##STR11##

Certain compounds or mixtures according to the invention are obtainable in a "one-pot-synthesis" as outlined in scheme IV: ##STR12##

Individual compounds of this type can be obtained according to schemes V to VII: ##STR13##

The reaction schemes mentioned above are to illustrate the invention without restricting it. The expert can choose other reaction methods without any inventive efforts.

In the following and in the preceding, all percentages given are percentages by weight. Temperatures are given in degrees Celsius.

The following examples are intended to illustrate the invention without restricting it.

EXAMPLE 1

The reactive liquid crystalline compound (1) ##STR14## is prepared via the sequence of reaction steps shown in scheme V. In step 4 of scheme V 2.2 moles TFAA are added dropwise to a solution 2 moles of the phenol obtained in step 3 of scheme V and 2 moles of the benzoic acid in 2 l of DCM.

The reaction mixture is stirred at room temperature for 16 hours. Then 5 moles of TEA in 1 l of DCM are added. The mixture is stirred for 16 hours. Aqueous work-up and column chromatography give (1) which shows K 111 S.

The following compounds are obtained analogously:

    __________________________________________________________________________       #STR15##                                                                     Compound No.     m          n          phase transition temperature                                                   (° C.)                           __________________________________________________________________________     (2)              3          5          K 76 N 160 I                              (3) 4 5 K 67 N 165 I                                                           (4) 4 6 K 78 S 82 N 159 I                                                      (5) 5 6 K 78 S 80 N 162 I                                                      Comp 1 4 4 K 105 N 164 I                                                       Comp 2 5 5 K 91 N 167 I                                                        Comp 3 6 6 K 105 (S 95) 152 I                                                __________________________________________________________________________

EXAMPLE 2 ##STR16##

p-hydroquinone is treated with 22 moles of TFAA followed by 2.5 moles of TEA.

A mixture consisting of 1 part comp 1 and 1 part comp 3 and 2 parts of Compound No. (4) is obtained which shows a melting point of 56° C. and a clearing point of 163° C.

Analogously a mixture of the following compounds is obtained:

    __________________________________________________________________________       #STR17##                                                                     n                    m                    parts                                __________________________________________________________________________     3                    3                    1                                      6 6 1                                                                          3 6 1                                                                          6 3 1                                                                        __________________________________________________________________________

This composition shows a melting point below 30° C. and a clearing point of 119° C.

EXAMPLE 3

A mixture of 0.5 moles of biphenol, 1.3 moles of potassium hydroxide, 0.6 moles of 3-bromopropanol and 0.6 moles of 3 bromohexanol is heated in 2 liters of butanone for 16 hrs. After aqueous work-up a mixture of ##STR18## is obtained.

This mixture is treated with 1.2 moles of acryloyl chloride and 1.2 moles of TEA in 1.5 liters of dichloroethane DCM and refluxed for 3 hours.

After aqueous work-up the resulting reactionmixture is purified by column-chromatography to yield a mixture of diacrylates (6), (7) and (8).

    __________________________________________________________________________       #STR19##                                                                     Compound No.   m         n         parts                                       __________________________________________________________________________     (6)            3         3         1                                             (7) 5 6 1                                                                      (8) 3 6 2                                                                    __________________________________________________________________________

Analogously a mixture of compounds of formulae (9), (10), (11) and (12) is obtained

    __________________________________________________________________________       #STR20##                                                                     Compound No.     m           n           parts                                 __________________________________________________________________________      (9)             3           3           1                                       (10) 6 6 1                                                                     (11) 3 6 1                                                                     (12) 6 3 1                                                                   __________________________________________________________________________ 

What is claimed is:
 1. A mixture of three or more direactive mesogenic compounds, which comprises at least one compound of each of the formulae IV, V and VI,

    R.sup.1 --(CH.sub.2).sub.m --O-MG-O--(CH.sub.2).sub.n --R.sup.2IV

    R.sup.1 --(CH.sub.2).sub.m --O-MG-O--(CH.sub.2).sub.m --R.sup.1V

    R.sup.2 --(CH.sub.2).sub.n --O-MG-O--(CH.sub.2).sub.n --R.sup.2VI

in which MG is a mesogenic group, m and n are different integers from 1 to 20, and R¹ and R² are each independently ##STR21## in which a is 0 or 1 and W is H, CH₃ or Cl, wherein said mesogenic compounds are obtained byc) treating a mesogenic diol of formula I,

    HO-MG-OH                                                   (I)

with a mixture of the halides of formulae II and III,

    X.sup.1 --(CH.sub.2).sub.m --R.sup.a                       (II)

    X.sup.2 --(CH.sub.2).sub.n --R.sup.b                       (III)

in the presence of a base wherein X¹ and X² are each independently Cl, Br or I, R^(a) and R^(b) are each independently --CH₂ OH or --CH═CWH and MG, W, m and n have the meaning given, and d) treating the resulting intermediatein the case of R^(a) and R^(b) being --CH₂ OH, with a vinyl derivative of formula CH₂ ═CW--(CO)_(a) --O-- or a reactive derivative thereof, in the case of R^(a) and R^(b) being --CH═CWH with a perbenzoic acid.
 2. A mixture of three or more direactive compounds according to claim 1, in whichMG is a mesogenic group of formula VIII,

    --(A.sup.1 --Z.sup.1).sub.o --A.sup.2 --                   VIII

in whichA¹ and A² are each independently(a) 1,4-phenylene in which one or two CH groups may be replaced by N; (b) 1,4-cyclohexylene in which one or two non-adjacent CH₂ groups may be replaced by --O-- or one --CH-- group may be replaced by --C(CN)--; (c) naphthaline-2,6-diyl;wherein optionally the (a) group is substituted by halogen, cyano or alkyl with 1 to 6 C atoms, Z¹ is each independently --COO--, --O--CO--, --CH₂ --CH₂ --, --C.tbd.C--, --CH₂ O--, --OCH₂ -- or a single bond, and o is 1, 2 or
 3. 3. A mixture of two or more direactive compounds according to claim 1, in which MG is selected from ##STR22## in which L is CH₃, Cl, F, OCH₃ or --CO--CH₃, andr is 0, 1, 2 or
 4. 4. A mixture of three or more direactive compounds according to claim 1, in whichn and m are given by the following table:

    ______________________________________                                         m      5          5     5        4   4                                           n 2 3 4 2 
 3.                                                                ______________________________________                                    


5. A mixture of two or directive compounds according to claim 1, in whichm-n≧1.
 6. A polymer obtained by polymerizing a mixture according to claim
 1. 7. A mixture of chemical intermediate compounds useful in preparing a mixture of direactive compounds according to claim 1, comprising mesogene-containing molecules, said mesogenes having two side chains attached thereto that contain a hydroxyl or vinyl group at the ends thereof, said mesogenes and said functional groups being separated by at least two to twenty spacer atoms,wherein both spacer groups have different chain length, which mixture is obtained by a) treating a mesogenic diol of formula I,

    HO-MG-OH                                                   (I)

with a mixture of the halides of formulae II and III,

    X.sup.1 --(CH.sub.2).sub.m --R.sup.a                       (II)

    X.sup.2 --(CH.sub.2).sub.n --R.sup.b                       (III)

in the presence of basein which MG is a mesogenic group, X¹ and X² are each independently Cl, Br or I, m and n are different integers from 1 to 20, and R^(a) and R^(b) are each independently groups selected from--CH₂ OH or --CH═CWH wherein W is H, CH₃ or Cl.
 8. A mixture of three or more direactive compounds according to claim 2, wherein at least one MG group is a three ring group wherein one of the two Z¹ groups is --COO-- or --OCO--, the other is a single bond and there are at least two lateral --Cl, --F, --CN or --CH₃ ring substituents.
 9. A mixture of three or more direactive mesogenic compounds of claim 1, wherein the method of obtaining the compound(s) is a one-pot synthesis.
 10. A composition of claim 1, wherein MG is selected from ##STR23## wherein L is CH3, CL, F, OCH3 or --CO--CH3 and r is 0, 1, 2 or
 4. 11. A composition comprising direactive compounds which comprises at least one compound of each of the formulae IV, V and VI

    R.sup.1 --(CH.sub.2).sub.m --O-MG-O--(CH.sub.2).sub.n --R.sup.2IV

    R.sup.1 --(CH.sub.2).sub.m --O-MG-O--(CH.sub.2).sub.m --R.sup.1V

    R.sup.2 --(CH.sub.2).sub.n --O-MG-O--(CH.sub.2).sub.n --R.sup.2VI

in which MG is a mesogenic group, m and n are different integers from 1 to 20, and R¹ and R² are each independently ##STR24## in which a is 0 or 1 and W is H, CH₃ or Cl, wherein MG is not ##STR25## wherein L is CH3, CL, F, OCH3 or --CO--CH3 and r is 0, 1, 2 or
 4. 12. A composition of claim 11, comprising three or more direactive compounds of the formula R¹ --(CH₂)_(m) O-MG-O--(CH₂)_(n) --R² wherein m, n, R¹, R² and MG are as defined in claim
 11. 13. A polymer obtained by polymerizing a composition according to claim 11, which is an oriented liquid crystalline polymer.
 14. An electrooptical scattering system which contains an oriented liquid crystalline polymer according to claim
 13. 15. A composition of claim 11, wherein m-n≧1.
 16. A composition of claim 12, wherein MG is a mesogenic group of formula VIII,

    --(A.sup.1 --Z.sup.1).sub.o --A.sup.2 --                   VIII

in whichA¹ and A² are each independently(a) 1,4-phenylene in which one or two CH groups may be replaced by N; (b) 1,4-cyclohexylene in which one or two non-adjacent CH₂ groups may be replaced by --O-- or one --CH-- group may be replaced by --C(CN)--; or (c) napthalene-2,6-diyl,wherein optionally group (a) is substituted by halogen, cyano, alkyl, alkoxy or alkanoyl with 1 to 6 carbon atoms, each Z¹ is independently --COO--, --O--CO--, --CH₂ CH₂ -- --C.tbd.C--, --CH₂ O--, --OCH₂ --or a single bond, and o is 1, 2 or
 3. 17. A composition of claim 12, wherein n and m are given by the following table:

    ______________________________________                                         m      5          5     5        4   4                                           n 2 3 4 2 
 3.                                                                ______________________________________                                    


18. A polymer obtained by addition polymerization of a compound according to claim
 11. 19. A method for preparing a mixture of three or more direactive mesogenic compounds which comprises:a) treating a mesogenic diol of formula I,

    HO-MG-OH                                                   (I)

with a mixture of the halides of formulae II and III,

    X.sup.1 --(CH.sub.2).sub.m --R.sup.a                       (II)

    X.sup.2 --(CH.sub.2).sub.n --R.sup.b                       (III)

in the presence of a base, in whichMG is a mesogenic group, X¹ and X² are each independently Cl, Br or I, m and n are different integers from 1 to 20, and R^(a) and R^(b) are each independently groups selected from--CH₂ OH or --CH═CWH wherein W is H, CH₃ or Cl, and b) treating the resulting intermediatein the case of R^(a) and R^(b) being --CH₂ OH, with a vinyl derivative of formula CH₂ ═CW--(CO)_(a) --O-- or a reactive derivative thereof, in which a is 0 or 1 in the case of R^(a) and R^(b) being --CH═CWH with a perbenzoic acid.
 20. The method of claim 19, whereinMG is a mesogenic group of formula VIII,

    --(A.sup.1 --Z.sup.1).sub.o --A.sup.2 --                   VIII

in whichA¹ and A² are each independently(a) 1,4-phenylene in which one or two CH groups may be replaced by N; (b) 1,4-cyclohexylene in which one or two non-adjacent CH₂ groups may be replaced by --O-- or one --CH-- group may be replaced by --C(CN)--; (c) naphthaline-2,6-diyl;wherein optionally the (a) group is substituted by halogen, cyano or alkyl with 1 to 6 C atoms, Z¹ is each independently --COO--, --O--CO--, --CH₂ --CH₂ --, --C.tbd.C--, --CH₂ O--, --OCH₂ -- or a single bond, and o is 1, 2or
 3. 21. The method of claim 19, wherein MG is ##STR26## in which L is CH₃, Cl, F, OCH₃ or --CO--CH₃, and r is 0, 1, 2 or
 4. 22. The method of claim 19, whereinn and m are given by the following table:

    ______________________________________                                         m      5          5     5        4   4                                           n 2 3 4 2 
 3.                                                                ______________________________________                                    


23. The method of claim 19, wherein the method is carried out in a one-pot synthesis. 